Broken bones, or fractures, are a common hazard of childhood. And although breaking a bone takes only a split-second fall off the jungle gym or a quick collision on the soccer field, the healing process takes a bit longer.

In most cases, a child who breaks a bone will require a cast to keep it still while it heals. Depending on the age of the child and the type of fracture, a cast can be on for as little as 4 weeks or as long as 10 weeks.

Some kids might find casts cool once they're on, but getting one can be frightening, especially if a child is in pain.

Knowing what happens in the ER or cast room might help alleviate some of that worry. The good news is that even though a broken bone can hurt and a cast or splint can be inconvenient, most kids recover with no trouble at all.

About Bones

An adult human skeleton has 206 bones, which begin to develop before birth. When the skeleton first forms in the womb, it is mostly made of flexible cartilage, but within a few weeks it begins to harden. This process is called ossification.

During ossification, cartilage is replaced by hard deposits of calcium phosphate and stretchy collagen, the two main components of bone. But in some areas, like the flat bones on top of the skull, connective tissue turns into bone instead.

Many bones of kids and teens contain "growing zones" called growth plates. These plates consist of columns of multiplying cartilage cells that grow in length and then change into hard bone. The growth plates are located at each end of the long bones (legs, arms, fingers, and toes). They determine the future length of the bone. When growth is complete, in mid-to-late adolescence, the growth plates close and become solid bone.

Types of Breaks

Because kids' bones are relatively soft and flexible, they tend to absorb shock better than adult bones. However, with enough force, they can still break. Due to their flexibility, though, they often bend into incomplete fractures (fractures that go partially through the bone), rather than break right through.

Types of incomplete fractures include:

buckle or torus fractures: one side of the bone bends, raising a little bump, without breaking the other side

greenstick fractures: a partial fracture in which one side of the bone is broken and the other side bends (resembling what happens when you try to break a green stick)

A complete fracture is one that extends completely through the bone. Types of complete fractures include:

closed fracture: the broken bone doesn't break the skin

open (or compound) fracture: the end of the broken bone breaks through the skin

non-displaced fracture: the pieces on either side of the break line up

displaced fracture: the pieces on either side of the break are out of line (which might require a procedure in the ER or surgery to make sure the bones are properly aligned before casting)

single fracture: the bone is broken in one place

segmental fracture: the bone is broken in two or more places

comminuted fracture: the bone is broken into more than two pieces or crushed

Growth plates are the weakest areas of the growing bones, so they tend to be more prone to injuries. Growth plate fractures can happen until kids reach late adolescence, and range from mild to serious. They require treatment by an orthopedic specialist.

Fortunately, kids' bones are natural healers. At the location of the fracture, the bones themselves will produce new cells and tiny blood vessels to help close up the break until it's almost as good as new. This repairing process is especially speedy in kids.

Before the Procedure

Although a doctor may be able to tell whether a bone is broken simply by looking at the injured area, he or she will also order an X-ray to confirm the fracture and determine exactly what type it is.

Your child will be brought into the X-ray room and asked to stay still while a special camera takes a picture of the bones in the injured area. You may stay with your child at this time as long as you are not pregnant (radiation exposure may be harmful to a developing fetus).

If your child is afraid of the machines, your reassurance can help him or her to remain still. Occasionally children may need to be restrained so that a clear, sharp image can be obtained. With cooperation, the whole process takes only a few minutes.

Most fractures are easily seen on an X-ray. However, a fracture through the growth plate often does not show up on X-ray. If this type of fracture is suspected, the doctor will treat it even if the X-ray doesn't show a break.

During the Procedure

What Is a Splint?

Splints are often the first type of treatment used when a doctor determines that a child has a broken bone. Unlike a cast, which completely surrounds a broken bone, a splint is hard only on one or two sides. A splint provides support and stabilization around an injury, thus decreasing the movement of the injured area and the child's pain. A splint also lowers the risk of further injury and allows room for swelling, which a cast does not.

Splints are often applied in the emergency room and are worn until a cast can be applied — usually a few days later or whenever the doctor has decided the swelling has subsided enough. For some injuries, usually those that are not fractures, a splint may be all that is necessary to stabilize the area during the healing process.

Applying a Splint

Splints may consist of three or four layers:

The first layer, which is optional, is cotton-stocking material that is intended to protect the skin and make the splint more comfortable.

The second layer is a soft cotton material that provides padding.

The third layer is made of plaster or fiberglass (usually fiberglass).

The final layer is usually an elastic bandage, which is wrapped around the splint and keeps everything in place.

If your child is treated with a splint, it's important to follow the doctor's instructions completely. Even though a splint is held in place by just a bandage, you should not attempt to rewrap or remove it, even if your child is experiencing some discomfort. Only a doctor or orthopedic technician should adjust your child's splint.

What Is a Cast?

Although some types of injuries can heal with just a splint, most fractures will need a cast. A cast is essentially a big, hard bandage that keeps a bone from moving during the healing process. It generally has two layers — a soft layer of padding that rests against the skin and a hard outer layer that protects the bone.

The inner layer is almost always made out of cotton, but occasionally a cast may have a special waterproof lining. The hard outside shell is made of either fiberglass or plaster:

Fiberglass, a moldable plastic, is the most commonly used cast material. When you see a cast that has a fancy pattern or color, it's a fiberglass cast.

Plaster is a heavy white powder that forms a thick paste that hardens when mixed with water. If plaster gets wet it causes problems with how the cast works and can even cause the cast to change shape.

Of the two, fiberglass lasts longer, weighs less, and allows X-rays to show the healing process better than plaster.

A cast is often applied by an orthopedist, a doctor who specializes in the care of bones, after the swelling has gone down. However, sometimes casts are applied by emergency room doctors, physician assistants, orthopedic technicians, or nurse practitioners.

Types of Casts

There are many types of casts, for all types of breaks. If your child has a break, chances are there's a specific cast to fix it.

The most common casts are:

short arm casts, which are placed from the knuckles of the hand to just below the elbow. These types of casts are used for forearm and wrist breaks and after some surgeries.

long arm casts, which go from the upper arm to the knuckles of the hand. These casts are generally used for upper arm or elbow fractures, but can also be used in forearm breaks.

short leg casts, which run from just below the knee to the bottom of the foot. These are usually used for ankle and lower leg breaks or surgeries.

long leg casts, which are applied from the upper thigh down over the foot. These casts are used to heal breaks and fractures of the knee, lower leg, or ankle.

short leg hip spica casts, which go from the chest to the knees and are used to keep hip muscles and tendons in place after surgery

Setting the Bone

For displaced fractures (in which the pieces on either side of the break are out of line), the bone will need to be set, or realigned, before a cast is put on so that it will heal in a straighter position.

When the doctor can straighten the bones from the outside of the injury it is called a closed reduction. During a closed reduction, pressure is applied to get the bone fragments back in place. Pain medicine and sedation are typically given through an IV in your child's arm if a closed reduction is necessary.

If the fracture is complicated or more serious, an open reduction might be necessary. Open reduction is a surgical procedure in which an incision is made in the skin and metal pins and plates are attached to the broken bone fragments to better stabilize the break while it heals. This is done under general anesthesia.

Applying the Cast

Having a cast put on is a relatively simple process. First, several layers of soft cotton are wrapped around the injured area. Next, the doctor wraps the plaster or fiberglass around the soft first layer. The outer layer is damp but will dry to a hard, protective covering. Doctors sometimes make tiny cuts in the sides of a cast so that there is room for swelling if it occurs.

After the Procedure

The first few days your child is in the cast are often the most difficult — for both of you. The area surrounding the break is probably still sore and swollen. The doctor may recommend acetaminophen or ibuprofen to help alleviate any pain.

The doctor may also recommend:

elevating the limb: Use something soft, like a pillow to raise the injured arm or leg above the heart to reduce swelling.

icing: Put ice in a plastic bag, and then place the bag over the injured area.

If the cast or splint is on an arm, the nurse or technician will give your child a sling to help support it. A sling is made of cloth and a strap that loops around the back of the neck and acts like a special sleeve to keep the arm comfortable and in place. A child with a broken leg who is mature enough will probably get crutches to make it a little easier to get around.

Sometimes a "walking cast" (a foot or leg cast with a special device implanted in the heel to allow for walking) can be given, though your child shouldn't walk on it until it's dry.

Cast-Care Tips

For bones to heal properly, certain steps must be followed to make sure the cast can do its job. These tips can help ensure your child's cast stays in good shape:

Keep non-waterproof casts dry. Many casts and splints are not waterproof, so keeping them dry is very important. The doctor may tell you to cover it with a plastic bag or special waterproof sleeve for baths or showers. If your child's cast or splint isn't waterproof and it gets wet, it may lose its strength and no longer be able to keep the injured bone in place. Wet cotton padding can also cause a rash or infection inside the cast. If your child's cast or splint gets wet, contact your doctor right away.

Keep out foreign objects or substances. At some point, the skin inside the cast will probably become itchy. Have your child avoid inserting anything into the cast to relieve itching. This could scrape the skin and lead to infection. You also should not pour baby powder, creams, or oils into the cast.

Check for cracks. Be sure to check the cast on a regular basis for cracks, breaks, tears, or soft spots. If you notice any of these things, contact your doctor.

Don't alter the cast. Although decorating the cast and having friends and family sign it are OK, doing things like pulling out the cotton lining or breaking off parts are not.

Risks and Complications

When splints and casts are applied properly and care instructions are followed, complications are rare. Sometimes sores can occur if the splint or cast is loose fitting and rubs the skin. These sores can become infected at times. Tight fitting splints or casts can cause fingers or toes to turn bluish — this can be relieved by fixing the cast or splint.

When to Call the Doctor

It's important to look for signs that your child's broken bone may require additional medical attention. Contact your doctor if you notice any of the following:

extreme tightness that leads to the hand or foot feeling numb or tingly

fingers or toes turning white, purple, or blue

loss of movement of toes or fingers

a blister developing inside the cast

any unusual odor or drainage coming from inside the cast

a break in the cast or the cast becoming loose

skin around the edges of the cast getting red or raw

fever

Fortunately, most problems can be quickly corrected if caught early.

Removing the Cast

Once the bone is healed, the cast will be removed with a small electrical saw. Although this saw may look and sound scary to your child, the process is actually very quick and painless. The saw's blade isn't sharp — it has a dull, rounded edge that vibrates from side to side. This vibration is strong enough to break apart the fiberglass or plaster but shouldn't hurt your child's skin. Don't attempt to remove the cast on your own.

Once the cast is off, the injured area will probably look and feel different to your child. The skin will be pale, dry, or flaky; the hair will look darker; and the muscles in the area will look smaller or thinner. This is all temporary. Over time, with some special exercises recommended by a doctor or physical therapist, the bone itself, as well as muscles around it, will be back in working order.